Reaction of B. cereus Bacteria and Peroxidase Enzymes under Pressures >400 MPa

It is known that B. cereus (Gram-positive bacteria) and peroxidase enzymes are resistant to pressures of ∼400 MPa in fruit and vegetable products among others. The aim of the present work is to have knowledge about their behavior when using pressures >400 MPa without other combined treatments. The results showed that B. cereus was not inactivated at pressures of 1000 MPa for 15 min at 20 °C. In peroxidase enzymes the results remained similar and the pressure of 1000 MPa for 30 min was not enough to inactivate them. The apple cell structure at these high-pressure levels revealed that it changed and the cells were less cemented. The treated apple presented a translucent aspect, and some fluids migrated from the inside to the outside of the cell. Keywords: High pressure; microorganisms; Bacillus cereus; peroxidase; apple; horseradish; cell structure